Several types of chairs are provided with reclining mechanisms. Certain reclining mechanisms in chairs include a base structure that allows the seat to slide forwards and backwards and cause inclination of the back part of the seat. Current locking mechanisms that are used to stop movement of the base structure and keep the seat base from sliding typically include nut and bolt type interfaces. However, this type of interface does not provide adequate locking capability for positioning of the seat. Bolt systems are typically not very performant and sometimes are subjected to problems after long periods of use.
Several different prior art chair adjustment mechanisms are known to the Applicant.
U.S. Pat. No. 5,066,069 (DeGelder) disclosed a chair having a seat and back adjustment mechanism in which a single handle is operated to hold or release both the seat and the back at selected independent angles. A series of plates on the seat and back are interleaved and positioned to be compressed by the handle.
WO 90/00871 (Lie et al.) teaches another locking device for chair seats. The device comprises several lamellae connected to the seat. Clamping shoes abutting against the outer lamellae may be clamped by bolts for locking the position of the seat in a certain configuration. The lamellae are aligned axially.
Other systems known to the Applicant include U.S. Pat. No. 3,966,253 (Berghof et al.); U.S. Pat. No. 5,584,533 (Schrewe); U.S. Pat. No. 5,718,481 (Robinson); U.S. Pat. No. 6,832,815 (O′Connor); U.S. Pat. No. 6,983,994 (Pino); U.S. Pat. No. 7,144,080 (Lloyd); US 2009/0243359 (Yoshida et al.); and EP 2 127 937 (Omori et al.).
Consequently, there is presently a need for a chair adjustment mechanism that offers improved performance and operates reliably over a longer period of time.